Metal rolling mill screw down control



July 14, 1931. w. R. WEBSTER ET AL 1,814,354

7 METAL ROLLING MILL SCREW DOWN CONTROL Filed Dec. 15, 1928 2Sheets-$heet l WM Q M MIMI' July 14, 1931. w. R. WEBSTER ET AL METALROLLING MILL SCREW DOWN CONTROL 2 Sheets-Sheet 2 Filed Dec. 15, 1928Patented July 14, 1931 WILLIAM R. WEBSTER AND WALTER R. GLARK, OFBRIDGEPORT,

CONNECTICUT METAL ROLLING- .MILL SCREW DOWN CONTROL Application filedDecember 15, 1928. Serial No. 526,333.

Our invention relates to a method of and of uniform hardness andtemperature, and apparatus for rolling metal, and more parthetemperature of the rolls remains conticularly to a method of andapparatus for stant, then the size of the pass can be adreducing metalsand other materials to justed to bring about the desired reduction vsheets or strips of uniform gauge or thickand no changes or adjustmentsthereafter ness. will be necessary. We have found, however,

The usual means for reducing metals and that when material of greater orless thickother materials to sheets or strips comprises ness or gauge,or of variable hardness, is dea plurality of mills arranged in tandem,livered to the mill the gauge of the material 0 each mill consisting oftwo or more metal delivered by the mill varies regardless of reducingrolls, the metals or other materials the fact that no apparent changetakes being passed between the reducing rolls of place in the size ofthe pass between the rolls the mills successively, each mill reducingthe of the mill. This is chiefly due to the fact thickness or gauge ofthe materials a certhat in rolling materials the spring or elas- 15 tainamount until the sheet or strip emerges ticity of the mill itself issuch that variafrom the last or final mill with the desired tions in thegauge of the material entering thickness or, gauge. persist, in likevariations of gauge in the The gauges of sheets or strips of materialmaterial leaving the mill in a more or less delivered by a final mill ofa series must be fixed percentage rate, while where the ma- 20 keptconstant within very narrow limits in terial is of variable hardness theresistance order to meet the standard gauge variations offered to therolls of the mill varies, with allowed by the trade, and in order tobring resulting changes in the gauge of the mathis about the severalcauses of gauge variaterial delivered.

tions must be kept constantly under control. It is, in general, anobject of the present There are four major causes of gaugevariainvention to provide a method and means for tions in the rolling ofmaterials in a rolling controlling the amount of reduction brought mill;first, that due to variations in the about by a rolling mill, in0rde rto deliver gauge of the materials entering between the material from themill having a uniform and rolls of the mill; second, that due tovariaconstant gauge or thickness. 7

tions in the hardness of the material being In a more specific aspect,it is an object rolled; third, that due to variations in the of thepresent invention to provide a methroll temperatures; and fourth, thatdue to 0d andmeans for compensating for changes changeskin roll contoursduring the rolling in the amount of spring ta 'ng place in a processes.mill due to differences in the amount of re- Of the several causes ofgauge variations, duction which takes place in the material we shallconcern ourselves chiefly in the prespassing through the mill. entapplication with those due to variations A further object of theinvention is to in the gauge of material entering between provide meansfor constantly gauging the the rolls of a mill and to variations in thematerial acted on by a rolling mill and open 40 hardness of the materiaing or closing the pass between the rolls ac- In the usual mill forrolling metal there is cording to the gauge of the material.

provided means for varying the size of the A still further object of theinvention is pass or opening between the metal reducing to provide amill in which the size of the rolls, and the mill operator constantlypass or opening between the metal reducing measures the thickness of thematerial derolls may be adjusted when the material livered by the milland adjusts the size of starts to pass through the mill, and in whichthe pass or opening, in order to correct any the gauge of the materialwill thereafter be variations which take place in the gauge of kept C nn Without further lltiOIl 011 the material delivered. If the materialdethe part of the operator.

livered to the mill is of a constant gauge and T0 t ese and other ends,the invention 1m novel features and combinabe hereinafter described andconsists in the tion of parts to claimed.

In the drawings,

Fig. 1 is a side elevation of a rolling mill showing a preferred form ofour invention used in connection therewith;

Fig. 2 is an end view of the same Fig. 3 is a view of a device used forgauging the material acted on by the mill; and

Fig. 4 is a view of an electric circuit used in connection with thecontrolling device.

In the above description of the nature and objects of our invention, wehave referred to the usual arrangement of mills in a tandem in metalreducing, and while our invention may be carried out with such anarrangement of mills it is by no means limited thereto but is of equalutility in instances where but a single reduction of the material takesplace, as for example, where it passes through a single mill.

It will be also understood that our invention is not limited to a millor mills having any particular type or arrangement of rolls therein, andthus while we shall describe our invention in connection with a two-rollmill, which is one of the simplest forms of mills in use, it will beunderstood by one skilled in the art that the invention may be carriedout with cluster mills, four-high mills, and various other forms.

Referring then to the drawings in which we have shown a preferredembodiment of our invention, the reference numeral 10 indicates, ingeneral, a mill stand or frame, having mounted therein a lower rollijlland an upper roll 12, the lower roll being mounted in relatively fixedbearings 13, while the upper roll is mounted in adjustable bearings 14.

The material being acted on by the rolls 11 and 12 enters between theserolls at A with an initial thickness T and emerges from between therolls with a final thickness T the amount of reduction being thedifference between these two thicknesses. It will be understood that inpractice a plurality of mills, such as that shown in Fig. 1, may beprovided and arranged in tandem, and that the material may passsuccessively through these mills, each mill reducing the material apredetermined amount. The amount of reduction brought about by each milldepends primarily upon the size or opening of the pass between the metalreducing rolls of the mill, and where a tandem of mills is used theoperator adjusts the rolls of the various mills of the tandem by hand tobring about a desired amount of reduction in each mill, being guided incontrolling the amount of reduction by the character of the materialbeing acted on by the mills and the desired guage in the materialemerging from the mills.

In order to ensure that the material passes from each mill with thedesired gauge, and in order to avoid the usual hand controlled methodsfor controlling the amount of reduction which depend for success of anoperator, we propose to control the size of the pass or opening in themill, or tandem of mills, by suitable means, the operation of which iscontrolled by the thickness or gauge of the material acted on. \Veprefer to control the size of the pass of a mill by means which iscontrolled by the thickness or gau e of the material as it leaves themill. I n carrying out our invention, we provide power means foradjusting the sizes of the passes in a mill or mills, which may be inthe form of hydraulic motors, electric motors, or other suitable primemovers, and control the operation of these means by a device whichgauges the material passing from the mills. As a suitable and preferredmeans for carrying out our invention, we shall now describe a mill inwhich the size of the pass is controlled electrically.

Referring again to the drawings, the reference numerals 15 and 16indicate adjusting screws mounted in threaded openings in the upper endsof spaced frame parts 17 and 18, screws 15 and 16 being provided withnoncircular ends 19 and 20, for the reception of a wrench, by means ofwhich the screws may be adjusted in frame 10 to move the roll 12 towardsoraway from roll 11. Mounted on the upper ends of frame parts 17 and 18are brackets 21 and 22, provided with bearings 23 and 24 for screws 15and 16, bearings 23 and 24 being spaced from the upper ends of frameparts 17 and 18.

Between bearing 23, on bracket 21 and the adjacent upper end of framepart 17, is a rotatable sleeve 25 mounted on and surrounding screw 15,sleeve 25 being provided with a screw 26 having an inner end 27,received in a longitudinally extending slot 28 in screw 15. On the lowerend of sleeve 25 is a worm wheel 29 having in engagement therewith aworm 30 mounted on the shaft 31 of reversible electric motor 32, shaft31 of motor 32 extending transversely of frame 10 and having mounted onthe opposite end thereof from motor 32 a second worm 33 in engagementwith a worm wheel 34 mounted on the lower end of sleeve 35, which isreceived on screw 16, below bracket bearing 24 and is provided with ascrew (not shown) similar to screw 26 in sleeve 25, which similarlyengages a longitudinally extending slot in screw 16. It will be readilyunderstood without further description that upon rotation of motor 32,sleeves 25 and 35 are rotated, thus producing rotation in screws 15 and16, through the medium of screws 26 and longitudinally extending slots27, the connection between sleeves 25 and 35 and upon the skill screws15 and 16 by means of screws 26 and slots 27 permitting longitudinalmovement of screws 15 and 16 relatively to sleeves 25 and 35.

Generally speaking, we propose to provide means for constantly gaugingthe material passing from the mill or mills, and controlling theoperation of the motor provided for adjusting the rolls by suitableconnections with the gauging means.

A suitable and preferred arrangement for this purpose is shown in Figs.1, 3 and 4 of the drawings, being designated generally by the referencecharacter 36, and comprising gauging device 37, which controls theoperation of switch 38, the latter being connected by suitableelectrical connections 39- to motor 32.

Gauging device 37 comprises a pair of arms 40 and 41 pivotally connectedtogether at 42, and having on their opposite ends from pivot 42 a pairof gauging rolls 43 and 44, between which the strip or sheetof materialpasses as it emerges from between the rolls of the mill. Mounted on'arm40 is a collapsible bellows or sylphon 45 filled with a suitable liquidwhich will conduct electricity, such as a salt water solution, andbellows 45 being connected by means of pipe 46 to liquid switch 38which, in general, may be made of a tube 47 of glass or other suitableinsulating material, and which is provided with oppositely disposedsealed-in contacts 48 and 49, above which are mounted another pair ofoppositely disposedsealed-in contacts and 51. Arms 40 and 41 are urgedtogether by relatively stiff tension spring 52, which is connected toarms 40 and 41 in any suitable or preferred manner. Mounted in athreaded opening in arm 41 is an adjusting screw 53, having a ball point54 bearing against the upper part of sylphon 45, sylphon 45 beingprovided with a filling plug 55. y

In order that the gauging device maybe sensitive to small changes. ofthe material passing between the gauging rolls, it is proposed toprovidea sylphon which has a cross-sectional area may times greater than thecross-sectional area of the liquid switch. For example, if the area ofthe bellows is one thousand times the area of the bore of the tube 47, amovement of the top of the bellows of .001 of an inch will move thesurface of the liquid in the tube one inch. Accordingly, if theterminals 48 and 49 are spaced a distance of one inch from terminals 50and 51, a very small movement of roll 43 relatively to roll 44 willproduce suflicient movement on the part of the liquid column to controlthe passage of an electric current between the terminals. Normally, whencontacts 48 and 49 are submerged in the liquid and contacts 50 and 51are above the liquid, the motor will be at in the thickness rest and therolls of the mill will remain at a constant relative adjustment.

If the material discharged by the rolls of the mill becomes of increasedgauge, it is apparent that rolls 43 and 44 will be separated from oneanother, permitting the level of the liquid in tube 47 to drop andopening the circuit in which the contacts 48 and 49 are connected, thiscircuit being such that through a relay the main switch controlling theoperation of motor 32 is closed, bringing the motor into rotation, andthrough the medium of sleeves 25 and 35 producing rotation in screws 15and 16 and movement of the rolls towards one another, thus reducing thegauge of the material as it emerges from the rolls and permitting therolls 43 and 44 to approach one another, whereupon the liquid rises intube 47 until it again closes a circuit in which contacts 48 and 49 areplaced, opening the main switch and stopping the motor. In case the,gauge of the material becomes less than it is desired, the rolls 43 and44 approach one another, thus forcing the liquid out of sylphon 45 andinto tube 47 until it bridges the gap between contacts 50 and 51, whichthrough a suitable relay close another main switch, which causes theoperation of motor 32 in a reverse direction, and finally the'separationof rolls 11 and 12 to bring about a greater gauge of the materialdischarged from between the rolls.

The mill may be set to deliver material of a particular thickness byplacing a piece of material of the desired thickness between rolls 43and 44, and then adjusting screw 53 until the liquid in tube 47 ismidway between contacts 48 and 50.

When the area of the sylphon is one thousand times the area of the boreof the tube and the terminals are placed one inch apart in tube 47, avariation in the material pass ing between the rolls 43 and 44 above orbelow a desired thickness sufficient to bring about a movement of .0005at the top of the bellows will cause the actuation of motor 32 toreadjust the pass between rolls 11 and 12 to bring the thickness of thematerial back to that desired.

Any suitable form of relays and-main switches for causing the actuationof the motor in reverse directions may be provided, that shown in Fig. 4forming an etlicient means for this purpose. Referring then to Fig. 4,the reference numerals 56 and 57 indicate a pair of main line wiresleading to anysuitable source of electrical energy, wire 56 beingconnected by lead 58 to terminal 59 of switch 60, and to terminal 61 ofswitch 62. Main line wire 57 is connected by lead 63 to terminal 64 ofswitch and terminal 65 of switch 62. 66 of switch 60 and terminal 67 ofswitch 62 are connected by a common lead 68 to Terminal flow of currentthroug voltage line wire 88,

motor 32, while terminal 69 of switch and terminal 70 of switch 62 areconnected by a common lead 71 to motor 32. Switches 60 and 62 areoperated by means of solenoids 72 and 73, respectively, and are eachnormally maintained in open posit-ion by means of springs 74 and 7Solenoid 72 is provided with a lead 76 connected to one wire 77 of thelow voltage line, while solenoid 7 3 is supplied with a lead 78connected to lead 76, and likewise to low voltage wire 77. The otherlead 79'from solenoid 72 is connected to a terminal 80 of relay switch81, while the other wire 82 of solenoid 73 is connected to a terminal 83of relay switch 84.. Terminal 85 of relay switch 81 and terminal 86 ofrelay switch 84 are connected by a common lead 87 to wire 88 of the lowvoltage line. Relay switch 81 is normally held in open position by meansof spring 89, while relay switch 84 is normally urged into closedposition by means of spring 90, relay switch 84 being held in openposition by means of solenoid 91, which is connected to contacts 48 and49 in switch 38, these contacts being normally bridged by the liquid inswitch 38, and permitting the lead 92 connected to wire 77 and throughthe lead 93 connected to wire 88, lead 93 passing to switch contact 49,while contact 48 is connected to solenoid 91 by means of lead 94. Relayswitch 81 is closed by means of solenoid 95, which is connected to lowvoltage line wire .7 7 by means of lead 92 and to contact 50 by means oflead 96, contact 51 being connected to the low voltage line wire 88 bymeans of lead 97 It will be readily understood that, when the liquid intube 47 is of sufficient height to bridge the gap between contacts 48and 49, current flows from lead 93 from low through the switch 38 andlead 94 to solenoid 91, and thence through lead 92 to low voltage linewire 77, thus energizing solenoid 91 and holding switch 84 in openposition. WVhen the level of the liquid in tube 47 falls below contacts48 and 49, the circuit leading to solenoid 91 is opened, thus permittingspring 90 to close switch 84 and permitting the flow of current throughsolenoid 73, energizing the latter and causing switch 62 to close, thuspermitting current to fiow through motor 32 and to produce rotation inscrewslzi and 16 to cause an approaching movement between rolls 11 and12.-

If the liquid level in tube 47 rises high enough to bridge the gapbetween contacts 50 and 51, the circuit leading to solenoid 95 isclosed, thus energiznig solenoid 95 and causing the closing of switch81, which permits current to flow through solenoid 7 2 to close switch60, which in turn permits the flow of current into motor 32, the flow ofcurrent in this case being in the reverse direction and producingmovement in motor 32 in the reverse direction to cause rotation inscrews 15 and 16 to bring about the separation of rolls 11 and 12 untilthe gauge of the material delivered by the mill becomes normal,whereupon the level of the liquid in tube 47 falls and opens thecircuit. esired, a double throw double pole reversing switch 98 may beprovided in the main line for causing the actuation of motor 32 by hand,while a single throw double pole switch 99 may be provided in the lowvoltage line for interrupting therethrough.

From the above description of the nature of our invention and thepreferred means for carrying it out, it will be seen that we haveprovided a means for constantly gauging the thickness of materialemerging from between the rolls of a mill, together with means forcausing adjustment of these rolls to correct variations in the gauge ofthe material as these variations may occur. The preferred embodimentdisclosed herein is capable of working within varying limits, it beingpossible with a large ratio between the areas of the sylphon and liquidto correct extremely small variations in the gauge of the material. Thusit will be seen that we have provided a method and means whereby arolling mill may be set to deliver material of a particular gauge, andin which variations in the thickness or hardness of mate-' rialsdelivered to the mill are automatically compensated for, so that thematerial emerges from between the rolls of the mill with a constantgauge.

While we have shown a ment of our invention, it is to be understood thatthe same is not to be limited to all the the flow of current detailsshown but is capable of modification and variation within the spirit ofthe invention and the scope of the appended claims.

What we claim is:

1. In a gauge controlling system for a rolling mill wherein the size ofthe pass between a pair of metal reducing rolls is adjusted by areversible electric motor, the combination of means for engaging thematerial being. rolled on opposite sides thereof, a fluid chamber onsaid means, a liquid level operated reversing switch for said motorconnected to said fluid chamber, and means on said material engagingmeans cooperating with said fluid chamber for controlling the liquidlevel in said switch.

2. In a gauge controlling system for a rolling mill wherein the size ofthe pass between a pair of metal reducing rolls is adjusted by areversible electric motor, the combination of a pair of arms pivotallyconnected together, means on said arms for ena 'ing the material onopposite sides thereswitch, and a connection between said bel-' with theliquid .level operated reversing switch for controlling said electricmotor, a connection between said fluid chamber and reversing switch, andmeans on said arms cooperating with said fluid chamber for varying theliquid level in said reversing switch.

3. In a gauge controlling system for a rolling mill wherein the size ofthe pass between a pair of metal reducing rolls is adjusted by areversible electric motor, the combination of a pair of arms pivotallyconnected together, material engaging rolls on the ends of said arms,means for urging said rolls into contact with opposite sides of thematerial, a collapsible bellows on one of said arms, an adjustableelement on the other of said arms in contact with a part of saidbellows, a liquid level motor controlling lows and switch.

4. In a gauge controlling system for a rolling mill wherein the size ofthe pass between a pair of metal reducing rolls is adjusted by poweroperated means, the combination of liquid level means for controllingthe operation of the power means, and means for varying the liquid levelin accordance gauge of the material acted on by the rolls.

5. In a gauge controlling system for a rolling mill wherein the size ofthe pass between a pair of metal reducing rolls is adjusted by areversible electric motor, the combination of a liquidlevel controlledswitch forcontrolling the operation of said motor, and means for varyingthe liquid level in said switch according to the gauge of the materialacted on by said rolls.

6. In a gauge controlling system for a rolling mill wherein the size ofthe pass between a pair of metal reducing rolls is adjusted by areversible electric motor, the combination of a pair of relativelymovable members between which material may be received to be gauged, aliquid chamber on one of said members, means on the other of saidmembers cooperating with the liquid contents thereof according to thegauge of the material received between the members, and a second liquidchamber connected to said first named chamber, the liquid level in saidsecond named chamber being controlled by the amount of liquid retainedin the first named chamber, and means controlled by the liquid level insaid second named chamber for controlling the operation of the motor.

7 In a gauge controlling system for a 1 011% ing mill wherein the sizeof the pass between a pair of metal reducing rolls is adjusted by areversible electric motor, the combination of a pair of relativelymovable members between which material may be received to be gauged, acollapsible liquid chamber on one of said members, said chamber being ofrelativcly large cross-sectional area, means on the other membercooperating with the liquid chamber to collapse the same to vary theliquid contents thereof according to the gauge of the material receivedbetween the members, and a second liquid chamber connected to said firstnamed chamber, said second liquid chamber being of relatively smallcross-sectional area, the liquid level in said second named chamberbeing controlled by the amount of liquid retained in the first namedchamber, and means controlled by the liquid level in the second chamberfor controlling the operation of the motor.

In witness whereof, we have hereunto set our hands this 13th day ofDecember, 1928. WVILLIAM R. WEBSTER. WALTER R. CLARK.

